/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.catalina.util;

import org.apache.juli.logging.Log;
import org.apache.tomcat.util.res.StringManager;

import java.io.*;
import java.lang.reflect.Proxy;
import java.util.Collections;
import java.util.Set;
import java.util.WeakHashMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.regex.Pattern;

/**
 * Custom subclass of <code>ObjectInputStream</code> that loads from the
 * class loader for this web application.  This allows classes defined only
 * with the web application to be found correctly.
 *
 * @author Craig R. McClanahan
 * @author Bip Thelin
 */
public final class CustomObjectInputStream extends ObjectInputStream {

	private static final StringManager sm = StringManager.getManager(CustomObjectInputStream.class);

	private static final WeakHashMap<ClassLoader, Set<String>> reportedClassCache =
			new WeakHashMap<ClassLoader, Set<String>>();
	private final Set<String> reportedClasses;
	private final Log log;
	private final Pattern allowedClassNamePattern;
	private final String allowedClassNameFilter;
	private final boolean warnOnFailure;
	/**
	 * The class loader we will use to resolve classes.
	 */
	private ClassLoader classLoader = null;

	/**
	 * Construct a new instance of CustomObjectInputStream without any filtering
	 * of deserialized classes.
	 *
	 * @param stream      The input stream we will read from
	 * @param classLoader The class loader used to instantiate objects
	 * @throws IOException if an input/output error occurs
	 */
	public CustomObjectInputStream(InputStream stream, ClassLoader classLoader) throws IOException {
		this(stream, classLoader, null, null, false);
	}

	/**
	 * Construct a new instance of CustomObjectInputStream with filtering of
	 * deserialized classes.
	 *
	 * @param stream                  The input stream we will read from
	 * @param classLoader             The class loader used to instantiate objects
	 * @param log                     The logger to use to report any issues. It may only be null if
	 *                                the filterMode does not require logging
	 * @param allowedClassNamePattern The regular expression to use to filter
	 *                                deserialized classes. The fully qualified
	 *                                class name must match this pattern for
	 *                                deserialization to be allowed if filtering
	 *                                is enabled.
	 * @param warnOnFailure           Should any failures be logged?
	 * @throws IOException if an input/output error occurs
	 */
	public CustomObjectInputStream(InputStream stream, ClassLoader classLoader,
	                               Log log, Pattern allowedClassNamePattern, boolean warnOnFailure)
			throws IOException {
		super(stream);
		if (log == null && allowedClassNamePattern != null && warnOnFailure) {
			throw new IllegalArgumentException(
					sm.getString("customObjectInputStream.logRequired"));
		}
		this.classLoader = classLoader;
		this.log = log;
		this.allowedClassNamePattern = allowedClassNamePattern;
		if (allowedClassNamePattern == null) {
			this.allowedClassNameFilter = null;
		} else {
			this.allowedClassNameFilter = allowedClassNamePattern.toString();
		}
		this.warnOnFailure = warnOnFailure;

		Set<String> reportedClasses;
		synchronized (reportedClassCache) {
			reportedClasses = reportedClassCache.get(classLoader);
			if (reportedClasses == null) {
				reportedClasses = Collections.newSetFromMap(new ConcurrentHashMap<String, Boolean>());
				reportedClassCache.put(classLoader, reportedClasses);
			}
		}
		this.reportedClasses = reportedClasses;
	}

	/**
	 * Load the local class equivalent of the specified stream class
	 * description, by using the class loader assigned to this Context.
	 *
	 * @param classDesc Class description from the input stream
	 * @throws ClassNotFoundException if this class cannot be found
	 * @throws IOException            if an input/output error occurs
	 */
	@Override
	public Class<?> resolveClass(ObjectStreamClass classDesc)
			throws ClassNotFoundException, IOException {

		String name = classDesc.getName();
		if (allowedClassNamePattern != null) {
			boolean allowed = allowedClassNamePattern.matcher(name).matches();
			if (!allowed) {
				boolean doLog = warnOnFailure && reportedClasses.add(name);
				String msg = sm.getString("customObjectInputStream.nomatch", name, allowedClassNameFilter);
				if (doLog) {
					log.warn(msg);
				} else if (log.isDebugEnabled()) {
					log.debug(msg);
				}
				throw new InvalidClassException(msg);
			}
		}

		try {
			return Class.forName(name, false, classLoader);
		} catch (ClassNotFoundException e) {
			try {
				// Try also the superclass because of primitive types
				return super.resolveClass(classDesc);
			} catch (ClassNotFoundException e2) {
				// Rethrow original exception, as it can have more information
				// about why the class was not found. BZ 48007
				throw e;
			}
		}
	}

	/**
	 * Return a proxy class that implements the interfaces named in a proxy
	 * class descriptor. Do this using the class loader assigned to this
	 * Context.
	 */
	@Override
	protected Class<?> resolveProxyClass(String[] interfaces)
			throws IOException, ClassNotFoundException {

		Class<?>[] cinterfaces = new Class[interfaces.length];
		for (int i = 0; i < interfaces.length; i++) {
			cinterfaces[i] = classLoader.loadClass(interfaces[i]);
		}

		try {
			return Proxy.getProxyClass(classLoader, cinterfaces);
		} catch (IllegalArgumentException e) {
			throw new ClassNotFoundException(null, e);
		}
	}
}
